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A109224
Minimum number of moves to solve the second Panex puzzle of order n of exchanging the two side towers.
1
3, 13, 42, 128, 343, 881, 2189, 5359, 13023, 31537, 76245, 184191, 444807
OFFSET
1,1
COMMENTS
Conjecture: for n >= 5, a(n) = ((7/2) * (7 - (4 * sqrt(2))) * (1 + sqrt(2))^n) - (8 * n) - 2 + ((7/2) * (7 + (4 * sqrt(2))) * (1 - sqrt(2))^n). Confirmed to n = 13, and known to be an upper bound for all larger n.
REFERENCES
Mark Manasse et al., The Panex puzzle, in Tribute to a Mathemagician, Peters, 2005, pp. 145-161.
CROSSREFS
Cf. A109175.
Sequence in context: A121162 A146018 A145946 * A106050 A074425 A041499
KEYWORD
hard,more,nonn
AUTHOR
EXTENSIONS
a(9) (found by David Bagley in 2008) and a(10)-a(13) (found by Derek Kisman in 2010) communicated by William Rex Marshall, May 27 2011
STATUS
approved